This invention relates to a knife sharpener, specifically to a new and improved non-serrated knife sharpener that is used to properly taper the blade directly behind the edge and also to hone the edge to a razor sharp condition.
Originally knife sharpening was done free-hand and would always result in an edge and edge bevel that was convex in profile. This human frailty is inevitable with every attempt no matter how experienced the person. A convex edge and edge bevel is considered inferior to an edge and edge bevel that is flat in profile. The latter can only be attained by using a grinding and honing angle controlled system.
Prior art has solved this inherent problem only minimally resulting in a reversion to the free-hand method to an extent.
U.S. Pat. No. 3,654,823 to Juranitch (1972) and U.S. Pat. No. 4,441,279 to Storm et al. (1984) both utilize clamping devices that attach directly onto the knife blade to hold the blade in a fixed position for sharpening. These clamps can become an obstacle during the tapering back of the knife blade and as a result both sharpening devices do not have the capacity to grind at very acute angles.
In the majority of instances, a proper tapering of a knife blade must be done and is crucial so that optimum performance of the knife is achieved. Both prior art clamping systems previously mentioned would hinder this process and consequently, a free-hand method would again be necessary.
There is no prior art non-electrical knife sharpening device available to the general public that will allow the user to not only hone the knife blade edge to a razor sharp condition, but in addition, allow the operator to adjust and maintain a multitude of blade angle choices during the edge bevel tapering process. In addition, there is no prior art that will allow the blade to be tapered properly with a multitude of controlled angle choices while the blade is unencumbered and free to traverse the abrasive without a clamping device attached to it.
Therefore, the only other alternative was the free-hand method. To this end, it is necessary to list several additional disadvantages of free-hand knife sharpening.
(a) As was painted out previously, free-hand sharpening will always result in an edge and edge bevel that is convex in profile. This convex shape cancels out the entire clearance angle directly behind the edge and consequently, drastically reduces the cutting ability of the knife.
(b) Repeated free-hand sharpening of a knife will quickly reduce the useful life of the tool because most of the metal that is ground away is being removed from the wrong locations, over and over again.
(c) Using improperly sharpened knives can, over time, result in hand, wrist, forearm, and shoulder afflictions.